New observations on the skull of Hesperornis with reconstructions of the bony palate and otic region
The skull of Hesperornis proves to be neognathous in the majority of diagnostic characters including the presence of the intrapterygoid joint. Most of the remaining characters, including those shared with the paleognaths, are primitive for Neornithes or all birds. In details of the braincase structure, Hesperornis is most similar to Enaliornis, Procellariiformes, Phaethon, and Fregata. A new reconstruction of the palate predicts the presence of the lacrimopalatine (uncinate) and the vomer.